1 files changed, 19 insertions, 2 deletions

diff --git a/drivers/gpio/gpio-ich.c b/drivers/gpio/gpio-ich.c
index f3eb1c52f97b..bfef20f8ab48 100644
--- a/drivers/gpio/gpio-ich.c
+++ b/drivers/gpio/gpio-ich.c
@@ -78,6 +78,12 @@ struct ichx_desc {
         /* Some chipsets have quirks, let these use their own request/get */
         int (*request)(struct gpio_chip *chip, unsigned offset);
         int (*get)(struct gpio_chip *chip, unsigned offset);
+
+        /*
+         * Some chipsets don't let reading output values on GPIO_LVL register
+         * this option allows driver caching written output values
+         */
+        bool use_outlvl_cache;
 };
 
 static struct {
@@ -89,6 +95,7 @@ static struct {
         struct ichx_desc *desc; /* Pointer to chipset-specific description */
         u32 orig_gpio_ctrl;     /* Orig CTRL value, used to restore on exit */
         u8 use_gpio;            /* Which GPIO groups are usable */
+        int outlvl_cache[3];    /* cached output values */
 } ichx_priv;
 
 static int modparam_gpiobase = -1;      /* dynamic */
@@ -106,14 +113,21 @@ static int ichx_write_bit(int reg, unsigned nr, int val, int verify)
 
         spin_lock_irqsave(&ichx_priv.lock, flags);
 
-        data = ICHX_READ(ichx_priv.desc->regs[reg][reg_nr],
-                         ichx_priv.gpio_base);
+        if (reg == GPIO_LVL && ichx_priv.desc->use_outlvl_cache)
+                data = ichx_priv.outlvl_cache[reg_nr];
+        else
+                data = ICHX_READ(ichx_priv.desc->regs[reg][reg_nr],
+                                 ichx_priv.gpio_base);
+
         if (val)
                 data |= 1 << bit;
         else
                 data &= ~(1 << bit);
         ICHX_WRITE(data, ichx_priv.desc->regs[reg][reg_nr],
                          ichx_priv.gpio_base);
+        if (reg == GPIO_LVL && ichx_priv.desc->use_outlvl_cache)
+                ichx_priv.outlvl_cache[reg_nr] = data;
+
         tmp = ICHX_READ(ichx_priv.desc->regs[reg][reg_nr],
                         ichx_priv.gpio_base);
         if (verify && data != tmp)
@@ -136,6 +150,9 @@ static int ichx_read_bit(int reg, unsigned nr)
         data = ICHX_READ(ichx_priv.desc->regs[reg][reg_nr],
                          ichx_priv.gpio_base);
 
+        if (reg == GPIO_LVL && ichx_priv.desc->use_outlvl_cache)
+                data = ichx_priv.outlvl_cache[reg_nr] | data;
+
         spin_unlock_irqrestore(&ichx_priv.lock, flags);
 
         return data & (1 << bit) ? 1 : 0;